Current supply circuit for television receivers



Dec. 22, 1953 CURRENT SUPPLY CIRCUIT FOR TELEVISION RECEIVERS H. DONN2,663,805

Filed June 21, 1952 L 00000. 000.. 23/ 7 X a M .32 30 37 6 Z5 Z7 INVENTOR.

m po/v/v Patented Dec. 22, 1953 CURRENT SUPPLY CIRCUIT. FOR TELEVISIONRECEIVERS Heinz. Donn,. Plorzheim, Germany, assignor to. International:Standard Electric; Corporation, New. York,v N.. Y. a. corporation: of;Delaware- Application June'2-1, 1952, Serial N 0. 294,781

(Jlaims-v priority, application Germany June 25, 1951.

4 Claims. (01. 307-12) This invention. relates generally to improvementsin. power supplies .of the full wave rectification type.

A primary object of the invention resides in the provision of a fullwave rectifier supply for delivering direct currentpotentials to aplurality of vacuum tubes some of which are to be operated at. certaintimes, and all. of which are to operated at other times.

More specifically, the invention is particularly applicable for use incombined television and high frequency radio chassis-wherein all of thevacuum tubes are used during television reception and only a portion ofvacuum tubes are used duringradio reception.

A still further object is to provide a double rectifier type of supplyincluding switch means for disabling operation of one of the rectifiersduring radio reception. and. connecting both of the rectifiers in amanner for cooperative operation during televisionuse when all of thevacuumtubes are employed.

A further object is to. provide a power supply of the above. typewherein the disabling of direct current potentials to a portion of thetubes doesnot-result ina risein the potential delivered to the othertubesinthecircuit.

Another object isv to provide a power supply which is adapted for usewith a main line A. C. voltage which may vary widely as to averagepotential.

Further obiectsand advantagesot the invention will become apparent topersons. skilled in the art upon an examination of the drawing, thedescription and the claims appended thereto.

The single drawing illustrates schematically a circuit arrangement of.power supply in which the present invention has been incorporated.

Referring to. the drawing, a main'transformer includes; the usualprimary winding 3.; a core 2 i, a high voltage centertappedsecondarywinw former, generically. designated Ill, the. oppositeend of primary Hlbeingconnected through lead it! and switch I3 backtothe. endofiwinding fi' and. to one side of an A. C. power. main.terminal 15, the opposite main terminal It being. connectg 5 and. a lowvo1tage..cathode. heater winding,

edto the other. endof primary 3 as shown. This tapped arrangementpermitsuse of the power supply on mains supplying potentials varyingfrom 110 to 240 volts.

Transformer H includes core i9, a pair of center tapped high voltagesecondary windings 20 and 2! and a low voltage cathodeheater windng 23.Secondary winding 5 of transformer 2 1s divided by center tap 25. intotwo equal coil portions 26 andZTLand center tapped secondaries 20 and 2iof transformer H are divided by their center taps Hand 3.! into equalcoil portions 32 33 and 3 35,, respectively. The outer end of CO1].portion 25. is series connected by lead 3? through coils 32,. 33 andlead 33 to anode 39 of a full wave rectifier tube 5. The Ad of coil isconnected by lead 42 and through coil ort ons 34, and lead '53 to theopposite anode 44 of. rectifier 40. Center taps 39 and of coils 20 and2.! are connected respectively through leads 46 and 4? to anodes 48 andto of full wave rectifier tube 52. The. cathode heater coils 5 and 23Vare connected in a conventional manner as shown to the. cathodes. 55 andof rectifier tubes 52 and respectively to complete the circuit.

The operation. of the device is a follows. Lead 68 serves as a commonnegative or ground lead from center tap 25 to the cathode of ground.nortionsof a circuitv to be. supplied with direct current voltages, asfor example, the radio portion of a combined television and radioreceiver. cathodes of the various tubes therein may be supplied withalternating heater curr nt frorn transformer 2. Lead 6!, taken from thecathode circuit of rectifier tube 52, serves as the positive lead to afilter and. then to the elements of the various vacuum. tubes requiringdirect current potentials, the usual dropping resis rs heine employed toprovide the selective potentials re quu'ed,,none o.f this conventionalcircuitry bein shown. 5

Assuming in the circuit shown that out ut oi. rectifier. 52 is. utilizedto supply the reouircd direct current operation potentials to the radiportion of a ccn'ibined-v television and radio re solver, andthattheoutput of rectifier M is utilized to supply operating potentialsto those vacuum tubes. which are. incorporated. in the television butnot in the radio circuit, the operation ot rec tifier tube 4!} isindependent of and unaffected by concurrent operation of rectifier tube52. Secondary coils 2G and 2i of transformer ii serve as a single centertapped secondary with the inner ends thereof maintained at zeropotential at the center tap 25 of the secondary coil 5 of transformer Itis apparent that since the respective inner ends of coils 2c and 21 areconnected by leads 3'7 and 22 to the respective outer ends of coil 5,voltage induced in coil 5 from primary 3, being equal and opposite inthe coil portions 25 and 27, does not alter the zero potential at theinner ends of coils 2t and 2! thus joined, hence lead 6%, connected tocenter tap 25 serves as a common negative or ground lead for bothrectifier tubes it and 52. The outer ends of coils 2t and 23 areconnected to anodes 39 and 5B of rectifier it through leads 38 and 43,thus rectifier it serves as a conventional full wave rectifier todeliver a positive output between leads it! and so.

Operation of rectifier 52 as described above is modified to some extentwith switch I3 closed and transformer ii operative. Whereas withtransformer i i inoperative, coil portions (:2 and 35 of secondaries 2dand 2! did not appreciably change the output of rectifier 52, with thetransformer H operative, coil portions 32 and 35 are serially added tocoil portions 2e and 2? respectively of secondary 5, transformer 2, toproduce a higher alternating current potential at anodes 48 and sorespectively of rectifier 52. The circuit connections between thetransformers are such that the induced voltages in coil portions 32 and35 of transformer it add to rather than oppose the induced voltages incoil portions 26 and 2? of transformer 2 respectively.

It is thus seen that for a given load, the rectified output potentialappearing between conduit 6! and 6B is somewhat greater when transformeri! is connected in circuit. As mentioned above, the output of rectifierib may be utilized to supply direct current potentials to those tubesemployed for television reception only, but a preferred use of the abovecircuit is as follows. The output of rectifier it may be employed tosupply only the very high operation potentials required by one or moreof the television circuit tubes, whereas the output of rectifier 52 maybe employed to supply operating potentials to all of the radio circuittubes plus some of the television circuit tubes. In this instance,cathode current for the radio circuit tubes is drawn from transformer 2whereas the cathode current for all of the television circuit tubes aredrawn from transformer ii. With transformer ii inoperative, therectified output between leads 5! and 58 is at an optimum value for theradio circuit tubes, and while certain of the television circuit tubesare connected to the same output, those tubes draw no current since nocathode heater current is supplied thereto. Upon closing switch it,heater current is supplied to the television circuit tubes, throwing agreater load on rectifier 52, which would normally result in 'a drop ofthe output potential between leads 5d and 6!. Because as aboveexplained, the output of rectifier 52 is higher with transformer Hoperating, the normally higher output ther from is reduced by theadditional load to stantially the value maintained on the radio circuittube elements with transforiner'ilin' operative.

It is thus seen that the circuit not only re-,

sults in economies due to a" saving in power consumption, but providessubstantially constant operating potentials for either a relatively fewtubes or a relatively large number of tubes, a result which couldotherwise only be obtained by providing a somewhat heavier power supplyshunted with a relatively heavy dropping resistance for maintenance offairly constant operating potentials irrespective of a major change inload. The circuit is therefore productive of. the additional advantageof substantially reduced construction costs since smaller transformersand rectifiers may be utilized than would otherwise be required.

While I have described above the principles of my invention inconnection with specific apparatus it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of my invention as set forth in the objects thereof and inthe accompanying claims.

What is claimed is:

1. In a circuit for supplying a plurality of electron discharge deviceswith cathode and anode Voltages, a main transformer including a primar acenter tapped high voltage secondary and a low voltage secondary, asecond transformer including a primary, a pair of center tappedsecondaries and a low voltage secondary, means switch connecting theprimary of said second transformer to the primary of said maintransformer, first and second full wave rectifiers each including twoanodes and a cathode, circuit means connecting the center taps of thesecondaries of said second transformer to the anodes respectively ofsaid first rectifier, with the outermost windings thereof connected tothe respective anodes of said second rectifier, and the innermostwindings thereof connected to the outermost windings of the centertapped secondary of said main transformer, and means connecting the lowvolt age secondary windings of said main and second transformers to thecathodes of said first and second rectifiers whereby direct currentoperating potentials for some of said devices may be obtained betweenthe center tap of the high voltage secondary or" said main transformerand the cathode of said first rectifier, and direct current potentialsfor other of said devices may be obtained between the said center tapand the cathode of said second rectifier.

2. In a device of the character described, a first transformer includinga primary, a high voltage center tapped secondary and a 'low voltagesecondary, a second transformer including a primary, a pair of highvoltage center tapped secondaries, .and alow voltage secondary, firstand second full wave rectifiers, means series connecting each of thehigh voltage secondaries of said second transformer between therespective ends of the high voltage secondary of said first transformerand the anodes, respectively, of said second rectifier, means connectingthe low voltage secondary windings of said first and second transformersto the cathodes of said first and second rectifiers respectively, andmeans con necting the center taps of' the high voltage secondarywindingof said'second transformer to the anodesof said first rectifier,whereby, in the absence of excitation current applied to the secondtransformer, said first rectifier is connected to thehigh voltagesecondary of said first transformer through portions -'of the tappedsecondaries of the second transformer to deliver full wave rectifiedoutput between the center tap of the high voltage secondary winding ofsaid first at one end thereof, the primary of said second 10 6transformer being connected to one of said taps and to the untapped endthereof.

4. The circuit of claim 1 wherein the primaries of said first and.second transformers are interconnected to provide selective impedance toa source of energizing current.

HEINZ DONN.

No references cited.

